The present invention relates to a three-side trimmer used for book binding process or the like.
A three-side trimmer for cutting (or trimming) the three sides, i.e., the top edge, the bottom edge and the front edge of a bound material is often used for finishing book binding in book binding process. The three-side trimmer is comprised of, as schematically shown in FIG. 7, a top edge trimming cutter 1 for cutting the top edge of a bound material to be trimmed (not shown), a bottom edge trimming cutter 2 for cutting the bottom edge of the bound material, a front edge trimming cutter 3 for cutting the front edge of the bound material, a cutting table 4 on which the bound material is supported and a pressing plate 5 pressing and fixing the bound material while cutting the bound material.
The trimming cutters 1, 2 and 3 are arranged substantially in a U-shaped manner above the cutting table 4 along the upper surface peripheral edge of the table 4. The top edge trimming cutter 1 and the bottom edge trimming cutter 2 are arranged to face each other in parallel with each other, with a distance corresponding to the distance between the top and bottom of the bound material from each other. The front edge trimming cutter 3 is arranged at right angle with respect to the top edge trimming cutter 1 and the bottom edge trimming cutter 2. Each of the trimming cutters 1, 2 and 3 is attached to a frame (not shown) for upward and downward movement in oblique direction by a drive. Each of the trimming cutters 1, 2 and 3 executes upward and downward movement between a wait position at which it is located above the upper surface peripheral edge of the cutting table 4 and a cutting position at which it is press-contacted with the upper surface peripheral edge of the cutting table 4.
Elongate blade receiving plates 4a, 4b and 4c made of, for example, hard rubber and receiving the corresponding trimming cutters are fixed in peripheral regions in such a manner that- they are press-contacted by the trimming cutters 1, 2 and 3 located at the cutting positions on the upper surface of the cutting table 4. Further, a pressing plate 5 is detachably attached to a tool which is ascended and descended by an elevator or the like, which is not shown.
During a cutting operation, the bound material is put on the upper surface of the cutting table 4 and the top edge, bottom edge and front edge thereof are positioned on the upper surfaces of the corresponding blade receiving plates 4a, 4b and 4c, respectively. Then the bound material is pressed by the pressing plate 5 and fixed to the cutting table 4. Thereafter, the top edge trimming cutter 1 and the bottom edge trimming cutter 2 are simultaneously descended from the wait positions to the cutting positions, the top edge and bottom edge of the bound material are cut and the top edge trimming cutter 1 and the bottom edge trimming cutter 2 are ascended to the wait positions. Then, the front edge trimming cutter 3 is descended from the wait position to the cutting position and the front edge of the bound material is cut. After the cutting operation, the front edge trimming cutter 3 is ascended to the wait position. Alternatively, after the bound material is fixed to the cutting table 4 by the pressing plate 5, the front edge trimming cutter 3 may move upwardly and downwardly so as to first cut the front edge of the bound material and then the top edge trimming cutter 1 and the bottom edge trimming cutter 2 may be simultaneously moved upwardly and downwardly to cut the top edge and bottom edge of the bound material.
In case of the conventional three-side trimmer, if the size of the bound material is changed, the distance between the top edge trimming cutter 1 and the bottom edge trimming cutter 2 needs to be changed. To do so, the top edge trimming cutter 1 and the bottom edge trimming cutter 2 are normally moved to be close to or away from each other in a direction parallel to the length of the front edge trimming cutter 3, thereby making the distance changeable. If the distance between the top edge trimming cutter 1 and the bottom edge trimming cutter 2 is changed, it is necessary to change the positions of the blade receiving plates 4a and 4b fixed to the cutting table 4. Due to this, cutting tables having sizes corresponding to the sizes of bound materials are prepared and appropriately replaced. However, the cutting table 4 is located just under the respective trimming cutters, so that a cutting table replacement operation is quite dangerous. Considering this, according to an improved three-side trimmer, a blade receiving plate 4c relating to a front edge trimming cutter 3 is fixed to a base, a cutting table 4 is constituted out of a pair of plate elements which can execute movement in approaching or separating directions parallel to the length of the blade receiving plate 4c, and a blade receiving plate 4a relating to a top edge trimming cutter 1 and a blade receiving plate 4b relating to a bottom edge trimming cutter 2 are fixed to the paired plate elements, respectively. By doing so, it is possible to change the positions of the blade receiving plates 4a and 4b without replacing the cutting table.
In the above-stated three-side trimmer, a bound material is located at a fixed position on the paired plate elements, at which position the three edges, i.e., the top edge, bottom edge and front edge of the bound material are cut. As a result, the front edge trimming. cutter 3 mechanically interferes with the top edge trimming cutter 1 and the bottom edge trimming cutter 2 if the blade 3 operates simultaneously with the top edge trimming cutter 1 and the bottom edge trimming cutter 2. To avoid this interference, the upward and downward movement of the front edge trimming cutter 3 is conducted at a predetermined time after the upward and downward movement of the top edge trimming cutter 1 and the bottom edge trimming cutter 2.
Nevertheless, because of the wear and the like of the constituent elements of the three-side trimmer, the staggered timing of the upward and downward movement of the front edge trimming cutter 3 with respect to the top edge trimming cutter 1 and the bottom edge trimming cutter 2 is shifted,.with the result that the front edge trimming cutter 3 interferes with the top edge trimming cutter 1 and the bottom edge trimming cutter 2 and the three-side trimmer is disadvantageously broken. Further, if the size of the bound material is changed, it is necessary to replace the pressing plate 5 in accordance.with the changed size. The replacement operation for the pressing plate 5 is, however, carried out in a narrow region surrounded by the respective trimming cutters 1, 2 and 3. Due to this, the operation is required to be carried out with the greatest possible care and is disadvantageously difficult to pursue.
It is, therefore, an object of the present invention to provide a three-side trimmer capable of preventing the mechanical interference of a front edge trimming cutter with a top edge trimming cutter and a bottom edge trimming cutter during operation and capable of dealing with different sizes of bound materials without the need to replace a pressing plate.
According to the present invention, the above object is attained by providing a three-side trimmer comprising: a frame; a cutting table supporting a bound material to be trimmed thereon; a top edge trimming cutter attached to the frame for upward and downward movement, and cutting a top edge of the bound material; a bottom edge trimming cutter attached to the frame for upward and downward movement and in parallel with the top edge trimming cutter, and cutting a bottom edge of the bound material; a front edge trimming cutter attached to the frame for upward and downward movement at right angle with respect to the top edge trimming cutter and the bottom edge trimming cutter with predetermined distances from one ends of the top edge trimming cutter and the bottom edge trimming cutter, and cutting a front edge of the bound material; a drive mechanism for effecting the upward and downward movement of the top edge trimming cutter, the bottom edge trimming cutter and the front edge trimming cutter; first and second blade receiving plates attached to face the top edge trimming cutter and the bottom edge trimming cutter right under the top edge trimming cutter and the bottom edge trimming cutter, respectively on the cutting table for receiving blade edges of the top edge trimming cutter and the bottom edge trimming cutter, respectively; a third blade receiving plate attached to face the front edge trimming cutter right under the front edge trimming cutter on said cutting table for receiving a blade edge of said front edge trimming cutter; a pressing plate attached to the frame for upward and downward movement, and pressing the bound material against said cutting table; the top edge trimming cutter and the bottom edge trimming cutter being arranged to move relatively to each other in a direction parallel to the length of the front edge trimming cutter in accordance with a size of the bound material; the cutting table comprising first and second table elements movable relatively to each other along the direction of movement of the top edge trimming cutter and the bottom edge trimming cutter, and a stationary third table element; first and second blade receiving plates attached to the first and second table elements, respectively, and a third blade receiving plate attached to the third table element; and a chuck mechanism gripping the bound material to be trimmed so as to move the bound material between at least two positions of a first cutting position at which the bound material is cut by the top edge trimming cutter and the bottom edge trimming cutter, and a second cutting position at which the bound material is cut by the front edge trimming cutter.
According to a preferred embodiment of the present invention, the frame comprises first and second frame elements movable relatively to each other along the direction of movement of the top edge trimming cutter and the bottom edge trimming cutter and a stationary third frame element. The top edge trimming cutter, the first table element and a first pressing plate pressing the bound material against the first table element and making an elevation movement are attached to the first frame element. The bottom edge trimming cutter, the second table element and a second pressing plate pressing the bound material against the second table element and making an elevation movement are attached to the second frame element. Relative movement of the first and second frame elements effect relative movement of the top edge trimming cutter and the bottom edge trimming cutter, relative movement of corresponding the first and second blade receiving plates and relative movement of.corresponding the first and second pressing plates.
According to another preferred embodiment of the present invention, the relative movement of the first and second frame elements are effected by movement of the first and second frame elements in opposite directions or by movement of one of the first and second frame elements with respect to the other one of said first and second frame elements of its rest position.
According to further preferred embodiment of the present invention, the chuck mechanism is provided with an auxiliary pressing plate pressing the bound material against the third table element.
According to further preferred embodiment of the present invention, the chuck mechanism comprises a grip head consisting of a fixed block and a movable block coupled to the fixed block through a vertical screw shaft so as to ascend and descend by rotation of the screw shaft, a motor attached to the lower portion of the fixed block for rotating the vertical screw shaft about its axis, a horizontal screw shaft and a guide rod attached to the frame and arranged parallel with each other along a direction parallel to the length of the top edge trimming cutter and bottom edge trimming cutter. The fixed block is provided with two penetrating holes in a direction parallel to the length of the top edge trimming cutter and bottom edge trimming cutter. One of the penetrating holes is provided with an internal thread for engaging with the horizontal screw shaft. The screw shaft is screwed into one of the penetrating holes and the guide rod is inserted into other of the penetrating holes. The chuck mechanism further comprises a shaft driving motor fixed to the frame, a first pulley mounted on one end of the screw shaft, a second pulley mounted on a drive shaft of the shaft driving motor, and an endless belt engaged with the first and second pulleys. Thus the grip head grips the bound material between its fixed block and movable block, and executes slide movement along the guide rod at least between the first cutting position and the second cutting position.